Abstract:

It is necessary to assess the intellectual functioning of dementia patients. However, psychometric instruments such as the Wechsler Adult Intelligence Scale - revised (WAIS-R) are often too demanding for dementia patients, precluding its utility. Clinicians and researchers have indirectly estimated a dementia patient's IQ from the Mini-Mental State Examination (MMSE). This measure is an eleven item screen instrument of global cognitive functioning. Fairly accurate estimates of IQ have been predicted using the MMSE total score.The purpose of the present study was to determine if it is possible to more accurately predict intellectual functioning when the individual MMSE items were used to predict Full Scale, Verbal, and Performance IQ using multiple regression analyses. Forty elderly dementia patients were administered both the MMSE and the WAIS-R. The MMSE total score was entered into a simple linear regression to predict FSIQ. In addition, the eleven item scores of the MMSE were entered into separate stepwise regressions to predict FSIQ, VIQ, and PIQ. The increment in the amount of variance accounted for in the FSIQ between the simple and multiple regression equations were evaluated for statistical significance.The results of these investigations revealed that while the multiple regression equations using MMSE item scores predicted a significant amount of the variance in IQ, they were not statistically superior to using the MMSE total score alone. The MMSE total score was found to account for 76.2% of the variance in Full Scale IQ. The MMSE items that were found to add significantly to the variance in intellectual level accounted for 80.9 %, 75.1 %, and 73.4 % of FSIQ, VIQ, and PIQ respectively. The results of the present study replicated other research that found the MMSE total score to accurately predict intellectual functioning in dementia patients.